1. Field of the Invention
The present invention relates to a glass container for medicinal purposes, and, more particularly, to a glass container for storing and preserving pharmaceutical or diagnostic solutions for medicinal purposes, which is provided with an anti-adherent coating on its interior surface or surfaces.
2. Prior Art
Glass containers for medicinal purposes, i.e. containers having pharmaceuticals or diagnostics as contents, are on the market in a most wide variety of embodiments, in order to take into account their respective purposes, associated administration forms and the respective contents.
Glass containers for medicinal contents should have interior surfaces which have the least possible adherence for their contents, i.e. as large as possible a wetting angle for aqueous contents, in order to permit a complete emptying of residues from the container. This is particularly true for comparatively small glass containers with very expensive contents.
Glass containers for medicinal purposes have been treated with silicone oils (polydimethylsiloxane oil) or silicone oil emulsions, in order to produce anti-adherent interior surfaces. This has been disclosed in U.S. Pat. No. A 2,504,482, among other prior art references. This method is also described in European medical formularies.
The main disadvantage of this method is that silicone oil is dispensed from the surfaces and that the silicone oil may be introduced into human or animal bodies. Furthermore undesirable adsorption phenomena occur on the silicone-coated surface. Protein binding is one of the undesirable adsorption phenomena and is particularly notable. Furthermore heavy metal impurities are unavoidably present in the silicone oil. Thus suitable expensive testing is prescribed In European formularies. Furthermore auxiliary substances (eg. detergents), which must be used for stabilizing silicone emulsions, are critical.
Methods for modification of the interior surfaces of the glass container using silanes, silazanes, etc, are known (GB 2,230,260 A) as well as by application of silicone oil. A monolayer is deposited on the surfaces from the liquid or gas phase after an expensive cleaning process, which often uses reactive acids, such as chromo-sulfuric acid, etc.
This process has the disadvantage that a fresh expensive washing process is required after the surface treatment, in order to remove the residual chemicals most completely. Furthermore no silane or silanized layers, which resist the action of the typical pharmaceutical tests sufficiently, which especially withstand autoclaving at 121xc2x0 C. for 20 minutes, are currently known.
It is an object of the present invention to provide a glass container for medicinal purpose of the above-described kind, so that its interior surface has an outstanding anti-adherent property, it is equal to the typical pharmaceutical stress test conditions and it introduces nosilicone into the solution found in the glass container.
According to the invention this object is attained with a glass container for storing and preserving pharmaceutical or diagnostic solutions for medicinal purposes, comprising a container closure device and an amorphous, transparent and pharmaceutically acceptable anti-adherent coating provided on the entire interior surface of the glass container over the entire interior surface up to the closure device, and wherein the anti-adherent coating has a contact angle for wetting with water of xe2x89xa780xc2x0, even after autoclaving at about 120xc2x0 C. for about 20 min, contains the elements Si, O, C and H and is deposited by means of a plasma-enhanced chemical vapor deposition method (PECVD), preferably by means of a plasma-pulsed, chemical vapor deposition method (PICVD).
Medicinal glass containers of this type, i.e. according to the invention, have interior surfaces that to a large extent reject water or wetting with water, which permits a nearly complete emptying of the container. It also has the great medically related advantage that no silicone substances are introduced into the pharmaceutical or diagnostic contents and thus into the human body.
Tests have shown that the anti-adherent layer or coating according to the invention is equal to typical pharmaceutical stress test conditions, e.g. typical sterilization conditions, without loosing its function. The glass container according to the invention is thus to a large extent pharmaceutically acceptable.
Preferably the anti-adherent layer comprises at least 1% by weight silicon and at least 5% by weight carbon. The hydrophobic properties of the coating can be augmented, when the anti-adherent coating contains fluorine according to a further embodiment of the invention.
According to a preferred embodiment of the invention the percentage content of fluorine in the anti-adherent layer is related to the percentage content of carbon by the following reciprocal relationship:
When fluorine less than 0.1% by weight, then Cxe2x89xa710% by weight;
When Fxe2x89xa70.1% by weight, then Cxe2x89xa75% by weight.